The invention concerns a method of measuring relative speed and in and out strokes in a motor-vehicle dashpot.
Dashpots are employed as links in the transmission of vibrations from the road surface to the body through the wheel suspension. The mechanisms are usually hydraulic, which ensures both comfort and safety.
German OS 3 11 909 190 discloses a sensor for a dashpot associated with semi-actively controlled wheels in a motor vehicle. The sensor detects relative speed, the difference between the speed of the body and that of the axle. It consists of a long coil connected directly or indirectly to the dashpot's piston rod and of a permanent magnet on the cylinder. The magnet induces a voltage in the coil.
This sensor can deliver only one signal, which represents the difference in speeds. It cannot be employed to detect and hence adjust how far the piston travels in and out.